Manufacture of fluoro-halo derivatives of hexachloroethane



Patented Aug. 21, 1934 UNITED STATES PATENT OFFICE MANUFACTURE OF FLUORO-HALO DERIVA- TIVES 0F HEXACHLOROETHANE No Drawing. Application April 10, 1931, Serial No. 529,285. Renewed October 31, 1933 4Cl'aima.

This invention relates to chemistry and chemical processes and more particularly to chemical processes for the manufacture of fluoro and/or halo-fluoro derivatives of hexachloroethane.

The objects of my present invention are to provide a process or processes for the manufacture of fiuoro and/or halo-fluoro derivatives of hexachloroethane by first reducing the melting point of the hexachloroethane and subsequently fiuorating the liquid so produced by the use of HF as a fiuorating agent.

As a specific example of my invention, the addition of 75 parts of antimony pentachloride to 213 parts of hexachloroethane, or the addition of 57 parts of antimony trichloride and 17 parts of chlorine to 213 parts of hexachloroethane, lowers the melting point of the 0201s from approximately 186 C. to about 130 C.

When the compounds are mixed in these proportions and slightly heated, the mixture will become a liquid. In this liquid state, the CzCls is fluorated by interacting HF with the liquid mixture.

In order to obtain C2CI2F4 in preference to other chlorofluorides, dephlegmation and control of the delivery of the reaction products are employed. The dephlegmation temperature is maintained at approximately 5 C. and the working pressure is maintained approximately at 1 atmosphere.

The dephlegmator returns CzClaFaCzChFa, CnClsF, and any unacted upon C2010 to the reaction chamber where these compounds are further fluorated to the desired extent.

The reactions taking place are substantially as follows:

In practice the process is made continuous by feeding the reactants CaClc and HF to the reaction chamber and by discharging the C2ChF4 and HCl from the top of the dephlegmator. The HCl may be separated from the C2ClzF4 in any known manner.

Other compounds such as CaClsF, CzCIaFa, or CaChFz can be obtained from CaClc by the method described above. In order to obtain any single one of these compounds in preference to the others, the temperature and pressure conditions are caused to approximate the vapor pressure characteristics of the desired compound. For example, it is advantageous to operate at about 48 C. and about 1 atmosphere to obtain a favorable yield of CzClaFa.

While I have disclosed a specific example of my process for obtaining C2C12F4 by dephlegmating at a temperature of substantially 5 C. at atmospheric pressures, and for obtaining CaClsF: by dephlegmating at a temperature of substantially 48 C. at atmospheric pressure, the process can be carried out at a higher or lower pressure with a corresponding change in temperature. The temperature and pressure of dephlegmation approximates the vapor pressure characteristicsof the desired product.

The preceding fluorations are described as onestep processes. However, the same results can be obtained by a plurality of multiple-step processes. As a specific example, C2CI4F2 can be obtained by fluoration of CzCle to CzClsF and subsequent fluoration of C2C15F to CzClrFz-similarly, C2F4Ch could be obtained by fiuoration of C2Clc to CaClaFa, and further fiuoration of the latter to C2C12F4.

While I have disclosed specific modes of reducing the melting point of CzCls, it should be understood that in its broad aspect my invention contemplates the fiuoration of CzClc by first reducing the melting point of the C2016 and then fiuorating by the interaction of HF with the liquefied CaClc.

What is claimed is as follows:

1. The process comprising lowering the melting point of CaClo and reacting with HF to replace at least one chlorine atom with fluorine.

2. The process comprising mixing with CaClc a substance capable of reducing its melting point, liquefying the mixture, and iluorating by reacting the liquefied mixture with HP to replace at vleast one chlorine atom with fluorine.

3. The method of manufacturing CaClzFi from CzCla which consists in mixing with CaCls a substance capable of lowering the melting point of the (helm liquefying the mixture, and reacting the liquefied mixture with HF.

4. The method of manufacturing C2ClzF4 comprising mixing an antimony halide with 0:01: to reduce the melting point of the CaClo, liquefying the mixture and interacting the liquefied mixture with HF to form C2CI2F4.

ALBERT L. HENNE. 

